In vitro skin models have shown excellent potential for the evaluation of acute skin irritation. However, the current systems lack the ability to discriminate between mild and strong irritants and require labor-intensive protocols that limit test throughput. To address the three critical limitations of current in vitro dermal irritancy assays, we propose to 1) identify alternative endpoints to discriminate between strong and weak dermal irritants 2) develop a skin model more representative of the human in vivo environment and 3) format this assay to improve assay throughput. This Phase I SBIR feasibility study will begin by identifying alternative endpoints using Stratatech's full-thickness StrataTest[unreadable] human skin model to improve the prediction of irritancy potential. StrataTest is a fully-stratified, three-dimensional human skin model consisting of dermal and epidermal compartments, recapitulating the tissue architecture and barrier function of human interfollicular epidermis. Once improved endpoints have been identified, test performance will be evaluated using a small set of reference chemicals and compared to the current protocols. The resulting procedures will then be transitioned to a higher-throughput 96-well format full-thickness skin model. These advancements will address the key limitations of current in vitro irritancy tests to enable more rapid and predictive assessment of irritancy potential.